diff --git a/prompt_toolkit/formatted_text/ansi.py b/prompt_toolkit/formatted_text/ansi.py
index 3d5706335..cebac9210 100644
--- a/prompt_toolkit/formatted_text/ansi.py
+++ b/prompt_toolkit/formatted_text/ansi.py
@@ -1,4 +1,5 @@
-from typing import Generator, List, Optional
+from string import Formatter
+from typing import Generator, List, Optional, Tuple, Union
 
 from prompt_toolkit.output.vt100 import BG_ANSI_COLORS, FG_ANSI_COLORS
 from prompt_toolkit.output.vt100 import _256_colors as _256_colors_table
@@ -257,11 +258,17 @@ def format(self, *args: str, **kwargs: str) -> "ANSI":
         Like `str.format`, but make sure that the arguments are properly
         escaped. (No ANSI escapes can be injected.)
         """
-        # Escape all the arguments.
-        args = tuple(ansi_escape(a) for a in args)
-        kwargs = {k: ansi_escape(v) for k, v in kwargs.items()}
+        return ANSI(FORMATTER.vformat(self.value, args, kwargs))
 
-        return ANSI(self.value.format(*args, **kwargs))
+    def __mod__(self, value: object) -> "ANSI":
+        """
+        ANSI('<b>%s</b>') % value
+        """
+        if not isinstance(value, tuple):
+            value = (value,)
+
+        value = tuple(ansi_escape(i) for i in value)
+        return ANSI(self.value % value)
 
 
 # Mapping of the ANSI color codes to their names.
@@ -275,8 +282,16 @@ def format(self, *args: str, **kwargs: str) -> "ANSI":
     _256_colors[i] = "#%02x%02x%02x" % (r, g, b)
 
 
-def ansi_escape(text: str) -> str:
+def ansi_escape(text: object) -> str:
     """
     Replace characters with a special meaning.
     """
-    return text.replace("\x1b", "?").replace("\b", "?")
+    return str(text).replace("\x1b", "?").replace("\b", "?")
+
+
+class ANSIFormatter(Formatter):
+    def format_field(self, value: object, format_spec: str) -> str:
+        return ansi_escape(format(value, format_spec))
+
+
+FORMATTER = ANSIFormatter()
diff --git a/prompt_toolkit/formatted_text/html.py b/prompt_toolkit/formatted_text/html.py
index 9a5213227..735ba2f1e 100644
--- a/prompt_toolkit/formatted_text/html.py
+++ b/prompt_toolkit/formatted_text/html.py
@@ -110,7 +110,7 @@ def format(self, *args: object, **kwargs: object) -> "HTML":
         """
         return HTML(FORMATTER.vformat(self.value, args, kwargs))
 
-    def __mod__(self, value: Union[object, Tuple[object, ...]]) -> "HTML":
+    def __mod__(self, value: object) -> "HTML":
         """
         HTML('<b>%s</b>') % value
         """
diff --git a/tests/test_formatted_text.py b/tests/test_formatted_text.py
index a49c67202..8b4924f96 100644
--- a/tests/test_formatted_text.py
+++ b/tests/test_formatted_text.py
@@ -103,6 +103,71 @@ def test_ansi_true_color():
     ]
 
 
+def test_ansi_interpolation():
+    # %-style interpolation.
+    value = ANSI("\x1b[1m%s\x1b[0m") % "hello\x1b"
+    assert to_formatted_text(value) == [
+        ("bold", "h"),
+        ("bold", "e"),
+        ("bold", "l"),
+        ("bold", "l"),
+        ("bold", "o"),
+        ("bold", "?"),
+    ]
+
+    value = ANSI("\x1b[1m%s\x1b[0m") % ("\x1bhello",)
+    assert to_formatted_text(value) == [
+        ("bold", "?"),
+        ("bold", "h"),
+        ("bold", "e"),
+        ("bold", "l"),
+        ("bold", "l"),
+        ("bold", "o"),
+    ]
+
+    value = ANSI("\x1b[32m%s\x1b[45m%s") % ("He", "\x1bllo")
+    assert to_formatted_text(value) == [
+        ("ansigreen", "H"),
+        ("ansigreen", "e"),
+        ("ansigreen bg:ansimagenta", "?"),
+        ("ansigreen bg:ansimagenta", "l"),
+        ("ansigreen bg:ansimagenta", "l"),
+        ("ansigreen bg:ansimagenta", "o"),
+    ]
+
+    # Format function.
+    value = ANSI("\x1b[32m{0}\x1b[45m{1}").format("He\x1b", "llo")
+    assert to_formatted_text(value) == [
+        ("ansigreen", "H"),
+        ("ansigreen", "e"),
+        ("ansigreen", "?"),
+        ("ansigreen bg:ansimagenta", "l"),
+        ("ansigreen bg:ansimagenta", "l"),
+        ("ansigreen bg:ansimagenta", "o"),
+    ]
+
+    value = ANSI("\x1b[32m{a}\x1b[45m{b}").format(a="\x1bHe", b="llo")
+    assert to_formatted_text(value) == [
+        ("ansigreen", "?"),
+        ("ansigreen", "H"),
+        ("ansigreen", "e"),
+        ("ansigreen bg:ansimagenta", "l"),
+        ("ansigreen bg:ansimagenta", "l"),
+        ("ansigreen bg:ansimagenta", "o"),
+    ]
+
+    value = ANSI("\x1b[32m{:02d}\x1b[45m{:.3f}").format(3, 3.14159)
+    assert to_formatted_text(value) == [
+        ("ansigreen", "0"),
+        ("ansigreen", "3"),
+        ("ansigreen bg:ansimagenta", "3"),
+        ("ansigreen bg:ansimagenta", "."),
+        ("ansigreen bg:ansimagenta", "1"),
+        ("ansigreen bg:ansimagenta", "4"),
+        ("ansigreen bg:ansimagenta", "2"),
+    ]
+
+
 def test_interpolation():
     value = Template(" {} ").format(HTML("<b>hello</b>"))
 
@@ -125,18 +190,18 @@ def test_interpolation():
 
 def test_html_interpolation():
     # %-style interpolation.
-    value = HTML("<b>%s</b>") % "hello"
-    assert to_formatted_text(value) == [("class:b", "hello")]
+    value = HTML("<b>%s</b>") % "&hello"
+    assert to_formatted_text(value) == [("class:b", "&hello")]
 
-    value = HTML("<b>%s</b>") % ("hello",)
-    assert to_formatted_text(value) == [("class:b", "hello")]
+    value = HTML("<b>%s</b>") % ("<hello>",)
+    assert to_formatted_text(value) == [("class:b", "<hello>")]
 
-    value = HTML("<b>%s</b><u>%s</u>") % ("hello", "world")
-    assert to_formatted_text(value) == [("class:b", "hello"), ("class:u", "world")]
+    value = HTML("<b>%s</b><u>%s</u>") % ("<hello>", "</world>")
+    assert to_formatted_text(value) == [("class:b", "<hello>"), ("class:u", "</world>")]
 
     # Format function.
-    value = HTML("<b>{0}</b><u>{1}</u>").format("hello", "world")
-    assert to_formatted_text(value) == [("class:b", "hello"), ("class:u", "world")]
+    value = HTML("<b>{0}</b><u>{1}</u>").format("'hello'", '"world"')
+    assert to_formatted_text(value) == [("class:b", "'hello'"), ("class:u", '"world"')]
 
     value = HTML("<b>{a}</b><u>{b}</u>").format(a="hello", b="world")
     assert to_formatted_text(value) == [("class:b", "hello"), ("class:u", "world")]